func anat 2 Flashcards
Newton’s 1st Law
Bodies in motion
tend to remain in motion.
Bodies at rest tend to
remain at rest
Force
An action or influence on
an object that produces or
prevents motion, or has a
tendency to do so
Internal force
Muscles and other
anatomical structures
External force
weights, braces,
therapist’s hands, gravity,
etc
objects movement (force) depends on…
Amount of force
Inertia
Mass
Friction
Qualities of Force
magnitude of direction
what represents qualities of force
vector (arrow)
Resultant Force
two or more forces acting on an object, the resultant
force, and therefore the movement of the object, is a
combination of the two forces.
concurrent force
creates resultant force
ex) gluteus medias
ex) Maureen and i pulling a rope to propel Brooklyn forward.
formula for finding torque
torque = force x length of lever arm
longer moment arm =
more torque
torque
force that produces rotation of a body segment around a relatively fixed axis.
Torque in Physiology…
If the biceps muscle pulls with 12 lbs of force, and
the insertion of the muscle is 2 inches from the axis
of rotation, then the torque produced is:
1/6 ft x 12 lbs = 2 ft*lbs
Lever arm: 2 inches or 1/6 ft
Force: 12 pounds
axis=elbow
biceps flexion=force
resistance=weight of forearm and hand
Muscles that pull superiorly or laterally to the axis of rotation…
Muscles that pull inferiorly or medially to the axis of rotation..
Muscles that rotate body part internally…
Muscles that rotate body part externally…
force couples
muscles act together to produce rotational movement by acting in equal and opposite directions, resulting in a single rotational movement
ex) screwing on a jar/water bottle lid
force couples in the shoulder…raising your arm
as you abduct your arm the deltoid generates an outward and upward force on the humerus. the infraspinatus, teres minor, and subscapularis counter this by generating a downward and inward force to keep the humerus in socket and stabilize the joint.
Simple Machines
pulleys and levers
pulley
change the direction of a force.
With a simple pulley, you pull
down, and the object goes up.
patella pulley
The patella, or knee cap,
acts as a pulley for the
muscle of the knee.
It changes the direction of
the pull of the muscle…
BUT, it also adds a
mechanical advantage to
the muscle.
It increases the lever arm of the
extensor mechanism, and thus
increase quadriceps strength by
up to 33–50%.
It increases the moment
arm, which in turn
increases torque
production
lever
increase force or
torque.
moment arm
the perpendicular distance from an axis to the line of action of a force
First class lever
Axis is located
between the force and
the resistance.
Ex: See-saw
F-A-R
F-A-R
first class lever
1st class levers in the human body
head on cervical
vertebrae. Muscles on one
side pull to maintain head
position, weight of head on
other side offer resistance
second class levers
Axis at one end, force at the
other end, and resistance in the
middle.
EX: Wheelbarrow
A-R-F
A-R-F
2nd class lever
2nd class levers in the human body
levers involve movement when
you are lowering an object to
the floor.
3rd class lever
Axis at one end, force
in the middle and
resistance at the end.
Shoveling
A-F-R
A-F-R
3rd class levers
stability
depends on BOS in relations to COG
is COG higher in males or females
COG is higher in males due to proportions
base of support
part of the body in contact
with the supporting
surface, including
the area between
the feet.
rules of stability (5)
- lower the COG, the more stable an
object. - greater the mass, the more stable an object.
- A line representing the
pull of gravity from the
COG must pass through
the BOS in order for an
object to be stable. - Stability is increased as the BOS
is enlarged. - Increased friction between the
object’s BOS and the surface
increases stability.
4 Joints in the Shoulder Complex
Three joints of the shoulder girdle:
◦ Sternoclavicular
◦ Acromioclavicular
◦ Scapulothoracic
One joint of the shoulder joint:
◦ Glenohumeral
Only bony attachment of the upper extremity (UE) to the axial skeleton
sternoclavicular joint
Sternoclavicular (SC) Joint
both stable AND mobile
Saddle shape joint with 3
degrees of freedom (DOF)
Elevates (frontal plane)
Depresses (sagittal plane)
Rotates (transverse plane)
Joint tightness in SC or AC
joint will limit shoulder
motion by up to 60 degrees.
Stabilized by the SC ligament,
and other structures.
Plane joint between
acromion of scapula and the
clavicle.
Acromioclavicular Joint
Acromioclavicular Joint
Two degrees of freedom.
Joint tightness in SC or AC
joint will limit shoulder
motion by up to 60 degrees.
Stabilized primarily by the
AC ligament, as well as the
coracoacromial ligament and
the coracoclavicular
ligaments.
Not a “true” joint, but the
articulation between the
scapula and the thorax.
Scapulothoracic Joint
Scapulothoracic Joint
Scapula moves into
Elevation
Depression
Abduction (protraction)
Adduction (retraction)
Upward rotation
Downward rotation
Scapulohumeral Rhythm
Grossly, 2:1 rhythm of
humerus to scapula
Of 180 degrees of abduction,
humerus is responsible for
about 120 degrees, scapula for
60 degrees
Glenohumeral Joint
Large ball on a relatively
small, flat “socket”
Three degrees of freedom
Mobility – lots!
Stability – mostly from
muscles
Glenohumeral ligaments
and coracohumeral ligament
concave convex rule
which surface is moving—
when a concave surface moves on a convex surface, the roll and glide occur in the same direction. Conversely, when a convex surface moves on a concave surface, the roll and glide occur in opposite directions.
Motions of the scapula
o Elevation and Depression
o Protraction and Retraction
o Upward and Downward Rotation
o Internal and External Rotation
o Tilt ↓
* Remember: normal distance
between medial borders of the
scapula is about 5 ‘’
joints of the elbow complex
Radiohumeral
Ulnohumeral
(Proximal radio-ulnar)
Bones of the elbow complex
Humerus
Radius
Ulna
Ulnohumeral joint
◦ Between the trochlear notch of
the ulna and the trochlea of the
humerus
Radiohumeral joint
Between the head of the radius
and the capitulum of the
humerus
The normal configuration of the
elbow shows a _____ degree “carrying
angle”
15-20
valgus
joint is positioned more
medially that the joints above and
below it.
ex) elbows ‘carrying angle’
Medial collateral
ligament of the elbow
Stabilizes against a
valgus force
Lateral collateral
ligament
Stabilizes against a
varus force
Forearm Joints
- Proximal radioulnar joint
- Distal radioulnar joint
forarm ligaments
Annular ligament
Interosseous membrane
Joint Movements of the forearm
pronation and supination
Joint Movements of the elbow
flexion and extension
valgus
pushes in toward the center of your body
varus
pushing out, away from the center of your body
She
Looks
Too
Pretty
Try
To
Catch
Her
Scaphoid
Lunate
Trilateral
Pisiform
Trapezium
Trapezoid
Capitate
Hammate
lateral to proximal row (starting at thumb) (palmar aspect of hand)
She Looks Too Pretty…
Scaphoid
Lunate
Trilateral
Pisiform
lateral to distal row (starting at thumb) (palmar aspect of hand)
Try To Catch Her…
Trapezium
Trapezoid
Capitate
Hammate
wrist joints
Distal radioulnar
Radiocarpal
Intercarpal
Mid-carpal
Carpometacarpal
Radiocarpal
between radius
and scaphoid, lunate
Intercarpal
“between the carpals”
Mid-carpal – “ in the middle
of the carpals”
Carpometacarpal
primary wrist joint responsible for 80% of movement
Radiocarpal Joint
Mid-Carpal Joint
Joint between the two rows of
carpals.
Wrist Movements
Wrist flexion
Wrist extension
Radial deviation
Ulnar deviation
Carpal Tunnel
Formed by the arched shape
of the carpal bones and the
transverse carpal ligament, or
flexor retinaculum.
The median nerve and nine
tendons run through here
80% of the forces across the
wrist occur at this joint
Radiocarpal Joint
between the radius
and the scaphoid and
lunate
wrist movements
Wrist flexion
Wrist extension
Radial deviation
Ulnar deviation
Joints of the Hand
CMC joints (5)
Intermetacarpal joints
MCP joints (5) – “knuckles”
PIP joints (4)
IP joint (1)
DIP joints (4)
thenar muscles
by base of thumb
Hypothenar muscle
by base of pinky
Intrinsic muscle
vs
Extrinsic muscle
intrinsic muscle are contained within a region such as the hand
extrinsic muscles move the fingers but are found outside of that region
Digiti
refers to the fingers
Minimi
refers to pinkie finger (5th digit)
Indicis
refers to
Index finger
anatomical snuff box
Region at the base of the
thumb
Made up of:
Extensor pollicis longus
on medial side
Extensor pollicis brevis
and abductor pollicis
longus on lateral side
Scaphoid (and part of the
trapezium) make the floor
Anatomical snuff box
tenderness can indicate a
_____
scaphoid fracture
Hand Movements
Flexion/extension of fingers
Abduction/ adduction of
fingers
Thumb flexion, extension,
abduction, adduction,
opposition
Types of Grips:
POWER Grips
spherical
cylindrical
hook
precision grips
Lumbrical-handing credit card
Tip-like pinch but curved fingers
Pinch-salt bay straight finger
Three jaw chuck-writing w/ pencil
Lateral pinch-putting coins in a vending machine?
Function of Spinal
Column
Protects the spinal cord
Neck and low back allow
lots of movement due to
many joints.
Discs absorb shock
how many
dof does the spinal chord have
3- triaxial
how many vertebrae are in the cervical spine
C1-C7 (7)
how many vertebrae are in the thoracic spine
T1-T12 (12)
how many vertebrae are in the lumbar spine
L1-L5 (5)
normal cervical curve
lordosis
normal thoracic curve
kyphosis- sacrum is extended- COUNTERNUTATION
normal lumbar curve
lordosis- sacrum is flexed- NUTATION
how many vertebra are in the sacral
5 fused
coccyx
tailbone at the bottom of the sacrum
normal sacral curve
kyphosis
Excessive protraction of the cervical spine: flexion of lower cervical
vertebrae, and extension of upper vertebrae
forward head position-Results in a
straightening of
the normal cervical
curvature
increased thoracic kyphosis
Occurs in sagittal plane
Is often accompanied with
forward head position
Scheuermann’s disease – one
cause of severe hyperkyphosis
Increased lumbar lordosis
Occurs in sagittal plane
Many possible causes
Scoliosis
Occurs in frontal plane
Many possible causes
cervical spine movements
Flexion/extension
◦ Mostly occurs from C2-7
Right/left side bending
◦ Mostly occurs from C2-7
Right/left rotation
◦ Almost half occurs at the A-A joint
Protraction/retraction
Thoracic and Lumbar
Spine Motions
Flexion/extension
Right/left side bending
Right/left rotation
C1
atlas
C2
axis- Dens or odontoid
process
facets
pairs of small joints in between the vertebrae in the back of the spine
cervical facets are in the ____ plane
transverse
thoracic facets are in the ___ plane
frontal, Long spinous process that
points down
Costal facets – articulates with
what structure?
tubercles of the ribs
lumbar facets are in the ___ plane
Facets lie in sagittal plane
why do lumbar have a larger body
support the weight of the upper body and withstand the stress of lifting and carrying heavy objects
The sacrum is not a flat
surface, but inclined about
___ degrees.
40
Intervertebral Disk anat
o Annulus fibrosus (outside)
o Nucleus pulposus (inside)
Flexion – What
happens to the “jelly
center” of the disk?
Extension – What
happens to the “jelly
center” of the disk?
flexion- squished forward
extension- squished backward
Most restricted movement of the spine
Thoracic spine – due to ribs,
shape of spinous processes
posterior pevlic tilt
decrease lordosis- eliminates natural curve of the spine
anterior pelvic tilt
increases lordosis
Muscle groups responsible for ant tilt
Spine extensors – contract to
pull up posterior pelvis
Hip flexors – contract to pull
down anterior pelvis
Muscle groups responsible for post tilt
Abdominals – contract to
pull up anterior pelvis
Hip extensors – contract
to pull down on posterior
pelvis
Lumbopelvic
Rhythm
relative pattern of the lumbar and pelvic contributions to trunk motion in the sagittal plan; requires hip and back extensors
(curve of spine when touching your toes)
Normal pelvic tilt is fairly minimal,
primarily due to actions of:
Hip abductor on stance side – pulls
down on pelvis, toward hip; this “hip
hiker” pulls up on unsupported side
pelvic girdle
hip bones/pelvis
sacrum
coccyx
Hip (“Inominate”) bones
◦ Ilium
◦ Ischiuim
◦ Pubis
Joints of the Pelvis
- Sacroiliac joints (SI)
- Pubic symphysis
- L5-S1 – lumbosacral
joint
Sacroiliac Joint
Synovial joint
Irregular plane joint
Many ligaments stabilize
Movement is minimal
2-4 mm in any direction
Pubic Symphysis
Ligaments on top and bottom
to strengthen join
Pubic bones join anteriorly,
with cartilage disk between
them
Lumbosacral Joint
Joint between L5 and S1.
Inclines at about a 40 degree angle to the horizontal.
Increased lordosis = increased angle.
